Search

Life on Earth uses DNA as the central template for self‐replication, genetic encoding, and information transfer. However, there are no physical laws precluding life's existence elsewhere in space, and alternative life forms may not need DNA. In the search for exobiology, knowing what to look for as a biosignature remains a challenge – especially if it is not from the obvious list of biologic building blocks. Clues from chemicals recently discovered on Mars and in the Taurus Molecular Cloud 1 (TMC‐1), show that intriguing organic compounds exist beyond Earth, which could provide a starting point for unconventional exobiotic designs. Here we present a new potential self‐replicating system with structural similarities to recently discovered compounds on Mars and TMC‐1. Rather than using DNA's hydrogen‐bonding motif for reliable base‐paring, our design employs sulfur‐nitrogen interactions to selectively template unique benzothiadiazole units in sequence. We synthesized and studied two versions of this system, one reversible and the other irreversible, and found experimental evidence of self‐replication in d‐chloroform solvent. These results are part of a larger pursuit in our lab for developing a basis for a potential exobiological system using starting blocks closely related to these cosmic compounds. [ABSTRACT FROM AUTHOR]

In the 19th century, postmortem brain examination played a central role in the search for the neurobiological origin of psychiatric and neurological disorders. During that time, psychiatrists, neurologists, and neuropathologists examined autopsied brains from catatonic patients and postulated that catatonia is an organic brain disease. In line with this development, human postmortem studies of the 19th century became increasingly important in the conception of catatonia and might be seen as precursors of modern neuroscience. In this report, we closely examined autopsy reports of eleven catatonia patients of Karl Ludwig Kahlbaum. Further, we performed a close reading and analysis of previously (systematically) identified historical German and English texts between 1800 and 1900 for autopsy reports of catatonia patients. Two main findings emerged: (i) Kahlbaum's most important finding in catatonia patients was the opacity of the arachnoid; (ii) historical human postmortem studies of catatonia patients postulated a number of neuroanatomical abnormalities such as cerebral enlargement or atrophy, anemia, inflammation, suppuration, serous effusion, or dropsy as well as alterations of brain blood vessels such as rupture, distension or ossification in the pathogenesis of catatonia. However, the exact localization has often been missing or inaccurate, probably due to the lack of standardized subdivision/nomenclature of the respective brain areas. Nevertheless, Kahlbaum's 11 autopsy reports and the identified neuropathological studies between 1800 and 1900 made important discoveries, which still have the potential to inform and bolster modern neuroscientific research in catatonia. [ABSTRACT FROM AUTHOR]

High‐speed‐cutting) milling is an extensively used production process in tool‐making and mold‐making industries. For the purpose of a self‐balancing tool, a hollow shaft is used and filled partially with a fluid. This talk presents different beam and shell models for the investigation of nonlinear vibrations. Therefore, different theories are compared with respect to the influence of geometrical nonlinearities, spin‐softening as well as stress‐stiffening, and also shear deformation. Additionally, a stochastic Wedig–Dimentberg approach is presented for the simulation of a spatial distributed unbalance. Starting with the nonlinear kinematics for the tool‐deformation Hamilton's principle is evaluated for the variational formulation of each model. Regarding to the shear deformation, the theories of Euler–Bernoulli and Ehrenfest–Timoshenko (beam models) as well as Kirchhoff–Love and Mindlin–Reissner (shell models) are used. In the following up, the variational formulation is discretized under usage of a global Ritz approach on the one hand, and on the other hand with a local finite element (FE) discretization. Afterward, the governing system of differential equations is solved and discussed. Different results of rotating and nonrotating tools are presented, which show the available options of each theory and also their limits. In particular, results of the eigenfrequencies including their stochastic distribution, stationary deformation, stability behavior, and various time solutions are shown. [ABSTRACT FROM AUTHOR]

In the last years, aeronautical industry has developed certified composite patch bonded repairs for damage tolerant structures, but only restoring metallic components. The mechanical behaviour of composite bonded repairs has been investigated since the development of composite damage tolerant structures is directly dependent on this technology. This study presents a strength prediction on carbon-epoxy adhesively repaired component, using ARALDITE® 2015 for the repairing and recurring to ABAQUS®, applying cohesive zone modelling (CZM), four different load conditions: tension, compression, upward bending and downward bending were tested. Four types of repairs are analysed: Single-Strap, Double-Strap, Scarf and Two-Stepped. The obtained results state that the Double-Strap repair withstand higher loads considering all the applied load cases when compared with the other geometries. Scarf and Two-Stepped repairs could achieve promising behaviours and they should be optimized, considering the advantages related to embedded patch repairing. Generally, the overlap length revealed to favour higher strengths, specially increasing from 5 to 10 mm. Failure paths were demonstrated, revealing proper relations with strength predictions. [ABSTRACT FROM AUTHOR]

Rotating fluid‐filled shell structures can be used for different applications in technique. Because of spin‐softening as well as stress‐stiffening it is essential to consider geometrical non‐linearities. Additionally, shear deformation is getting important in case of thick shells. At this point different theories from KIRCHHOFF‐LOVE (no shear deformation) and MINDLIN‐REISSNER (first order shear deformation) are compared with each other. For both theories the nonlinear kinematics are shown and therewith the HAMILTON's principle is evaluated to receive the equations of motion. The solution of the corresponding eigenvalue problem is done with a global RITZ approach on the one hand, on the other hand with local FE‐discretization. Different results of rotating and non‐rotating cylindrical shells with respect to their eigenfrequencies are presented and compared. Furthermore, experimental data is used for validation. [ABSTRACT FROM AUTHOR]

Raman microscopy and refractive near-field profilometry were used to analyze waveguides written in Yb-doped Kigre QX glass under the low repetition-rate (noncumulative-heating) regime. It was found that femtosecond-laser induced refractive index change was due to an increase in the proportion of Q1 P-tetrahedra and the associated increase in the polarizability of the glass. The role of color center formation and removal in this process is clearly defined, phosphorous–oxygen hole centers (POHCs) and PO3- ions form as a result of P–O bonds being broken during the modification process, and the subsequent removal of POHCs give rise to the increased proportion of Q1 P-tetrahedra. This result, when compared to other studies undertaken in the cumulative-heating regime, show conclusively that the mechanism of refractive index change in a particular type of glass can be very different, depending on the irradiation conditions. [ABSTRACT FROM AUTHOR]

Until now several studies of rotating structures like rings or shells have been done. To model such problems in a right way, geometrical nonlinearity has to be considered. Different methods can be used, to solve the corresponding eigenvalue problem. In this article the focus will be placed on the finite element method. In contrast to flat elements curved ones can cause some numerical inconveniences. They include a tremendous loss of convergence on the one hand, on the other hand the appearance of zero energy modes. In addition, centrifugal and Coriolis effects have to be taken into account. For certain examples the results of different FE‐models are shown and compared with global approaches as well as measurement data. [ABSTRACT FROM AUTHOR]

Open cell foams are widely used in engineering which includes an application in areas, where vibration excitations can act on the structures. Therefore dynamical properties as eigenfrequencies and eigenmodes are of particular interest, which show a dispersion due to the stochastic characteristic of the microstructure. To avoid time consuming measurements a simulation algorithm will be presented which enables to estimate the distribution of the eigenfrequencies. In order to do this the microstructure has to be addressed as well as different weights of several specimen, which have an influence on the computed and measured eigenfrequencies. [ABSTRACT FROM AUTHOR]

Chalcogen bonding (CB) is the focus of increased attention for its applications in medicinal chemistry, materials science, and crystal engineering. However, the origin of sulfur's recognition properties remains controversial, and experimental evidence for supporting theories is still emerging. Here, a comprehensive evaluation of sulfur CB interactions is presented by investigating 2,1,3‐benzothiadiazole X‐ray crystallographic structures gathered from the Cambridge Structure Database (CSD), Protein Data Bank (PDB), and own laboratory findings. Through the systematic analysis of substituent effects on a subset library of over thirty benzothiadiazole derivatives, the competing interactions have been categorized into four main classes, namely 2S–2N CB square, halogen bonding (XB), S⋅⋅⋅S, and hydrogen‐bonding (HB). A geometric model is employed to characterize the 2S–2N CB square motifs and discuss the role of electrostatic, dipole, and orbital contributions toward the interaction. Sulfur square interactions predominate the crystal lattices of diverse 2,1,3‐benzothiadiazole structures, yet the origin and robustness of these close contacts has not been experimentally examined. A comprehensive X‐ray evaluation sheds light on the nature of these interactions and their implications for chalcogen bonding. [ABSTRACT FROM AUTHOR]

Symmetry-adapted perturbation theory (SAPT) calculations are carried out to elucidate the intermolecular interactions present between fluorinated and nonfluorinated alkyl chain groups and aromatic π systems in the folded and unfolded conformers of Wilcox torsion balance systems. The calculations predict the folded conformers to be 2.0-2.3 kcal/mol more stable than the unfolded conformers, with the preference for the folded conformer being greater in the fluorinated alkyl chain case. We also establish that a simple electrostatic analysis, based on atomic charges, is inadequate for understanding the conformational preferences of these systems. In the folded conformers, there are sizable charge penetration contributions that are not recovered by point charge models. Additionally, the SAPT analysis reveals that exchange-repulsion interactions make a significant contribution to the relative stability of the folded and unfolded conformer. [ABSTRACT FROM AUTHOR]

Social insect castes (e.g., queens, workers) are prime examples of phenotypic plasticity (i.e., different phenotypes arising from the same genotype). Yet, the mechanisms that give rise to highly fertile, long-lived queens versus non-reproducing, short-lived workers are not well understood. Recently, a module of co-expressed genes has been identified that characterizes queens compared to workers of the termite Cryptotermes secundus (Kalotermitidae): the Queen Central Module (QCM). We tested whether the QCM is shared in termite species, in which queens gradually develop via early larval and late larval instars, the latter functioning as totipotent workers (linear development). Similar as in C. secundus, gene expression profiles revealed an enrichment of QCM genes in Zootermopsis angusticollis queens, a species from another termite family (Archotermopsidae). The expression of these QCM genes became gradually enriched during development from early larval instars via workers to queens. Thus, our results support the hypothesis of a conserved genetic toolkit that characterizes termite queens with gradual linear development. Our data also imply a strong caste-specific tissue specificity with the QCM signal being restricted to head-prothorax tissues in termite queens. This tissue-specific expression of key aging-related genes might have facilitated the evolution of a long lifespan in termite queens. [ABSTRACT FROM AUTHOR]

Since January 1st 2022, catatonia is (again) recognized as an independent diagnostic entity in the 11th revision of the International Classification of Diseases (ICD-11). This is a relevant time to systematically review how the concept of catatonia has evolved within the 19th century and how this concept changed under the influence of a wide variety of events in the history of psychiatry. Here, we systematically reviewed historical and modern German and English texts focusing on catatonic phenomena, published from 1800 to 1900. We searched five different electronical databases (https://archive.org , www.hathitrust.org , www.books.google.de , https://link.springer.com and PubMed) and closely reviewed 60 historical texts on catatonic symptoms. Three main findings emerged: First, catatonic phenomena and their underlying mechanisms were studied decades before Karl Ludwig Kahlbaum's catatonia concept of 1874. Second, Kahlbaum not only introduced catatonia, but, more generally, also called for a new classification of psychiatric disorders based on a comprehensive analysis of the entire clinical picture, including the dynamic course and cross-sectional symptomatology. Third, the literature review shows that between 1800 and 1900 catatonic phenomena were viewed to be 'located' right at the interface of motor and psychological symptoms with the respective pathophysiological mechanisms being discussed. In conclusion, catatonia can truly be considered one of the most exciting and controversial entity in both past and present psychiatry and neurology, as it occupies a unique position in the border territory between organic, psychotic and psychogenic illnesses. [ABSTRACT FROM AUTHOR]

Although fluorine often plays an influential role in molecular recognition, little is known about the effect of aliphatic fluorine on the CH-π interaction in solution. A series of molecular balances were synthesized that contain fluorinated and nonfluorinated alkyl groups. Our findings indicate that fluorine's polarizing ability does enhance CH-π binding and depends on molecular orientation. Surprisingly, when the terminal end of the alkyl group is completely fluorinated, the balance tips toward fluorophobicity and assumes an unusual constrained conformation. [ABSTRACT FROM AUTHOR]

Denitrification results in the formation of two gaseous end-products: radiatively active greenhouse gas nitrous oxide (N2O) and radiatively inert di-nitrogen (N2). Measuring N2produced by soil microorganisms has historically been difficult because of interference by high background concentrations (780,840 ppm) of atmospheric N2.Here, we applied a new automated technique for simultaneous measurement of the denitrification end-products N2O and N2. We tested the hypothesis that the temperature response function (defined here as Q10) for N2O was greater than for N2under anaerobic conditions in the laboratory. The Q10for N2O was 2.0 and the Q10for N2was 1.4, indicating differences in sensitivity to temperature. Denitrified-N shifted towards N2O as temperature increased. While moisture strongly controls the relative abundance of denitrification end-products, additional experiments are needed to determine how a wider range of temperatures may affect N2O and N2. Results could enhance understanding of temperature controls on N2O production and consumption processes. [ABSTRACT FROM PUBLISHER]

The number of microfluidic strategies aimed at separating particles or cells of a specific size within a continuous flow system continues to grow. The wide array of biomedical and other applications that would benefit from successful development of such technology has motivated the extensive research in this area over the past 15 years. However, despite promising advancements in microfabrication capabilities, a versatile approach that is suitable for a large range of particle sizes and high levels of enrichment, with a volumetric throughput sufficient for large-scale applications, has yet to emerge. Here we describe a straightforward method that enables the rapid design of microfluidic devices that are capable of enriching/removing particles within a complex aqueous mixture, with an unprecedented range of potential cutoff diameter (below 1 μm to above 100 μm) and an easily scalable degree of enrichment/filtration (up to 10-fold and well beyond). A simplified model of a new approach to crossflow filtration – controlled incremental filtration – was developed and validated for its ability to generate microfluidic devices that efficiently separate particles on the order of 1–10 μm, with throughputs of tens of μL min−1, without the use of a pump. Precise control of the amount of fluid incrementally diverted at each filtration “gap” of the device allows for the gap size (~20 μm) to be much larger than the particles of interest, while the simplicity of the model allows for many thousands of these filtration points to be readily incorporated into a desired device design. This new approach should enable truly high-throughput microfluidic particle-separation devices to be generated, even by users only minimally experienced in fluid mechanics and microfabrication techniques. [ABSTRACT FROM AUTHOR]

Wilcox torsion balances with well-defined 'folded' and 'unfolded' configurations provide a facile experimental probe of noncovalent interactions in solution. Recent modifications to the torsion balance bridgehead (Bhayana and Ams in J Org Chem 76:3594, ) provide new insights into the distance dependence of noncovalent interactions. We explore these systems using dispersion-corrected density functional theory calculations and continuum model solvents. The results quantify the role of bridgehead flexibility and point to the importance of folding entropy and noncovalent interactions in the unfolded configuration. [ABSTRACT FROM AUTHOR]

Abstract: The mobility of neptunium (V) in subsurface high ionic strength aqueous systems may be strongly influenced by adsorption to the cell wall of the halophilic bacteria Chromohalobacter sp. This study is the first to evaluate the adsorption of neptunium (V) to the surface of a halophilic bacterium as a function of pH from approximately 2 to 10 and at ionic strengths of 2 and 4M. This is also the first study to evaluate the effects of carbonate complexation with neptunium (V) on adsorption to whole bacterial cells under high pH conditions. A thermodynamically-based surface complexation model was adapted to describe experimental adsorption data under high ionic strength conditions where traditional corrections for aqueous ion activity are invalid. Adsorption of neptunium (V) was rapid and reversible under the conditions of the study. Adsorption was significant over the entire pH range evaluated for both ionic strength conditions and was shown to be dependent on the speciation of the sites on the bacterial surface and neptunium (V) in solution. Adsorption behavior was controlled by the relatively strong electrostatic attraction of the positively charged neptunyl ion to the negatively charged bacterial surface at pH below circum-neutral. At pH above circum-neutral, the adsorption behavior was controlled by the presence of negatively charged neptunium (V) carbonate complexes resulting in decreased adsorption, although adsorption was still significant due to the adsorption of negatively charged neptunyl-carbonate species. Adsorption in 4M NaClO4 was enhanced relative to adsorption in 2M NaClO4 over the majority of the pH range evaluated, likely due to the effect of increasing aqueous ion activity at high ionic strength. The protonation/deprotonation characteristics of the cell wall of Chromohalobacter sp. were evaluated by potentiometric titrations in 2 and 4M NaClO4. Bacterial titration results indicated that Chromohalobacter sp. exhibits similar proton buffering capacity to previously studied non-halophilic bacteria. The titration data were used to determine the number of types, concentrations, and associated deprotonation constants of functional groups on the bacterial surface; the neptunium adsorption measurements were used to constrain binding constant values for the important neptunium (V)-bacterial surface species. Together, these results can be incorporated into geochemical speciation models to aid in the prediction of neptunium (V) mobility in complex bacteria-bearing geochemical systems. [Copyright &y& Elsevier]

The combination of ultrafast laser inscription and engineered soft glasses is enabling a new class of photonic devices offering long wavelength transparency, high nonlinearity, and optical gain. However, this field of research also possesses its own unique set of fabrication challenges, which range from the predictable, such as self-focusing effects, material stress, and damage to the unexpected, such as photo-induced index changes of different sign. In this article, we review many of the fabrication challenges surrounding ultrafast laser-written soft-glass photonics and highlight these by comparing and contrasting laser processing of common soft glasses in both the athermal and thermal writing regimes. [ABSTRACT FROM AUTHOR]

Since the first report of triple-chain silicates in 1977, there has been considerable uncertainty about their formation in nature, primarily concerning whether they are stable minerals or an intermediate step in the formation of other chain or sheet silicate minerals. The lack of thermochemical data and relevant experimental studies for any triple-chain silicate has impeded establishment of their thermodynamic stability relative to other minerals. Here we combine recently reported thermochemical data for a sodium-analog of the triple-chain silicate clinojimthompsonite (Na-cjt) with existing data for various common minerals (i.e., enstatite, talc, anthophyllite, and chrysotile). We also present new experimental data to show that Na-cjt should form stably at typical metamorphic conditions of 0.2 GPa and 450 °C. Ion-activity vs. pH diagrams calculated at 100-300 °C and 0.1 GPa show that Na-cjt could form by reaction between primary igneous minerals (enstatite, forsterite) in oceanic harzburgite and seawater at temperatures up to 300 °C. However, formation of Na-cjt from harzburgite that has been altered to talc and chrysotile is not expected to occur, except at the unusually high pH conditions observed for forearc serpentine mounds. Estimates of the thermochemical properties of the Na-free end-member clinojimthompsonite [Mg10Si12O32(OH)4] suggest that it also should form from the primary mineralogy of harzburgite at temperatures and Si concentrations typically observed for various oceanic hydrothermal and geothermal systems, but probably not from ultramafic rock already hydrated to serpentine. [ABSTRACT FROM AUTHOR]

Previous studies investigating the role of the operating parameters on ultrafast laser ablative generation of gold nanoparticles have reported a wide range of nanoparticle size distribution and plasmon resonant properties. In some cases the reported role of fluence and other processing parameters is contradictory. In this systematic investigation, we deconstruct and examine the role of the component parts of fluence, namely pulse energy and ablation spot size, on nanoparticle generation. Other parameters such as exposure time and scan speed are also studied. We show that the nanoparticle average size and distribution is related to different contributions from pulse energy, pulse repetition frequency and spot size. We also correlate the average particle size and distribution with the wavelength and width of the plasmon resonance peak, and apply Mie theory in order to develop clearer physical insights into the mechanisms dominating nanoparticle generation. [ABSTRACT FROM AUTHOR]

Iron deficiency anemia is the most common nutritional deficiency among children. This cross- sectional, descriptive and quantitative study is part of a multicenter project, which verified the prevalence of anemia in children aged three to 12 months, treated by a health service unit in Ribeirão Preto, SP, Brazil. Interviews with mothers and determining hemoglobin dosage were carried out with 121 children who participated in the study. Two international criteria were adopted as parameters of anemia according to the children's age. Descriptive statistics, measures of central tendency and associations were used for data analysis. The prevalence of anemia among 69 children aged three to 5 months was 20.2% and 48.0% among 52 children aged six to 12 months. The total prevalence of anemia was 32.2%. There was significant association between anemia and children's age, and anemia and the consumption of liquid cow's milk. [ABSTRACT FROM AUTHOR]

Colloidal gold nanoparticles were produced by irradiating a gold disc with a femtosecond laser beam in pure deionized water. Variation of laser fluence between 38 and 330 J/cm2 was used to control the nanoparticle size distribution. The nanoparticles produced were spherically shaped with average diameter between 9 and 10 nm. The effect of ablation time on the nanoparticle production efficiency and size distribution was also studied. [ABSTRACT FROM AUTHOR]

Chinese people are consistently reported to be less likely to commit to posthumous organ donation than the Westerners. This study aims at investigating how death anxiety may hinder them from expressing their willingness to donate organs. Among 290 Hong Kong Chinese adults (age >= 25 years), a higher level of death anxiety was associated with a greater expectation of medical neglect and a lower level of self-efficacy. Moreover, a higher level of death anxiety was also correlated with a lower likelihood of donor card signing and discussion of organ donation. The results of regression analyses suggested a mediating role of self-efficacy on the relationship between death anxiety and these behaviors. That is, death anxiety, by lowering one's perceived self-efficacy, reduces his/her likelihood to sign the donor card or to tell his/her donation decision. Findings suggest that death education program should be included in promotion campaigns for Chinese adults. [ABSTRACT FROM AUTHOR]

Problems related to alcohol abuse have been associated to different factors, regardless of the causes attributed to this phenomenon. Alcohol consumption and dependence is considered a public health problem and deserve attention because of the social, work, family, physical, legal and violence-related risks it represents. This study aimed to identify the effects of alcoholism on family relations and, by means of case management, to encourage the recovery of these relationships. The results show that the problems caused by alcohol abuse impose profound suffering to family members, which contributes to high levels of interpersonal conflict, domestic violence, parental inadequacy, child abuse and negligence, financial and legal difficulties, in addition to clinical problems associated to it. [ABSTRACT FROM AUTHOR]

Since family permission is necessary for organ procurement to occur in China, family discussions about posthumous organ donation are crucial for increasing the actual organ donation and transplant rate. However, this study found that among 298 Chinese young adults, most of them (88%) were reluctant to talk about organ donation with their families. Based on the Theory of Reasoned Action, this study investigated communication within families about organ donation. Psychological factors included intention, attitude, subjective norm, death anxiety, and knowledge. As expected, the subjective norm was more powerful than attitude in explaining family discussions among Chinese people. Death anxiety, but not misconception, also significantly lowered the likelihood of family discussion. It is concluded that future campaigns for lessening death anxiety and promoting the social norm for organ donation must be conducted in Chinese societies, in order to encourage family discussions and improve the donation rate. [ABSTRACT FROM AUTHOR]

HSC (High Speed Cutting) milling is one of the most common production processes in tool‐making and mold‐making industries. One aim of current investigations is a better understanding of the dynamics of a tool shank with high slenderness. Often the revolution speed is higher than the lowest eigenfrequencies of the tool shank, so that resonance can appear during run‐up or run‐out. The focus will be placed on the influence of an unbalance. Starting with the geometrical nonlinear kinematics for the strains, the Hamilton's principle is evaluated to obtain the variational formulation of the tool shank. The unbalance is implemented with a stochastic WEDIG‐DIMENTBERG model. In the following‐up RITZ approach is used for discretization and the eigenfrequencies are computed. Afterwards the results are discussed for certain examples. [ABSTRACT FROM AUTHOR]

This study examines the effect of bacterial metabolism on the adsorption of Cd onto Gram-positive and Gram-negative bacterial cells. Metabolically active Gram-positive cells adsorbed significantly less Cd than non-metabolizing cells. Gram-negative cells, however, showed no systematic difference in Cd adsorption between metabolizing and non-metabolizing cells. The effect of metabolism on Cd adsorption to Gram-positive cells was likely due to an influx of protons in and around the cell wall from the metabolic proton motive force, promoting competition between Cd and protons for adsorption sites on the cell wall. The relative lack of a metabolic effect on Cd adsorption onto Gram-negative compared to Gram-positive cells suggests that Cd binding in Gram-negative cells is focused in a region of the cell wall that is not reached, or is unaffected by this proton flux. Thermodynamic modeling was used to estimate that proton pumping causes the pH in the cell wall of metabolizing Gram-positive bacteria to decrease from the bulk solution value of 7.0 to approximately 5.7. [ABSTRACT FROM AUTHOR]

We are investigating photoresponsive molecules called "precipitons" that undergo a solubility change co-incident with isomerization. Isomerization can be induced by light or by catalytic reagents. Previous work demonstrated that covalent attachment of a metal complex, Ru(II)(bpy)3, greatly accelerates photoisomerization and influences the photostationary state. In this paper, we describe precipitons (1,2- biphenylethenes; analogous to stilbenes) that are activated by a covalently attached organic sensitizer (benzil). We find that isomerization of these stilbene analogues is little effected by the presence of benzil in solution but that the intramolecular benzil effect is to increase the rate of isomerization and to significantly change the photostationary state. What is most interesting about these observations is that the precipiton is the primary chromophore in this bichromophoric system (precipiton absorbance is many times greater than benzil absorbance in the 300-400 nm range), yet the neighboring benzil has a significant effect on the rate and the photostationary state. The effect of unattached benzil on the rate was small, about a 24% increase in rate as compared with 4-6-fold changes for an attached benzil. We speculate that the isomerization process occurs by a "round-trip" energy-transfer mechanism. Initial excitation of the precipiton chromophore initiates a sequence that includes (1) formation of the precipiton singlet state, (2) singlet excitation transfer from the precipiton unit to the benzil, (3) benzil-centered intersystem crossing to the localized benzil triplet state, (4) triplet energy transfer from the benzil moiety back to the precipiton, and (5) isomerization. [ABSTRACT FROM AUTHOR]

We have investigated light-triggered or catalytically activated precipitation agents and have proposed the name "precipiton" for such molecules or molecular fragments. A phase separation is induced when the precipiton isomerizes to a low-solubility form. In this paper we describe the first intramolecularly activated precipitons. The isomerization process is induced by intramolecular triplet energy transfer from a covalently attached metal complex. As expected, intramolecular sensitization leads to a more rapid isomerization than can be achieved by intermolecular sensitization at accessible concentrations. Two isomeric bichromophoric precipiton species, each containing [Ru(bpy)3]2+ and 1,2-bis(biphenyl)ethene units covalently linked together by an ether tether, have been synthesized and characterized, and their photochemical properties have been investigated. The rates of photoisomerization of these complexes, [((Z)-1,2-bis(biphenyl)ethene-bpy) Ru(bpy)2](PF6)2 (2Z) and [((E)-1 ,2-bis(biphenyl)ethene-bpy)Ru(bpy)2](PF6)2 (2E), were compared to those of their untethered analogues, (Z)-i ,2-bis(biphenyl)ethene-OTBS (1Z) and (E)-1,2-bis(biphenyl)ethene-OTBS (1E), where ruthenium sensitization occurred through an intermolecular pathway. Upon irradiation with visible light (λ ≥ 400 nm) in degassed solution, 2Z/E and 1Z/E obeyed reversible first-order rate kinetics. The intramolecularly sensitized precipiton 2Zisomerized 250 times faster (k2z-2E = 1.0 × 10-3 s-1 with a 51% neutral density filter) than the intermolecular case 1Z (k1Z-1E = 0.80 × 10-5 s-1). For 1E and 2E,the isomerization rates were k1E-1Z= 11.0 × 10-5 s-1 and k2E-2Z= 1.6 × 10-3 s-1, respectively. The average Z/E mole ratio at the photostationary state was 62/38 for 2Z/E and 93/7 for 1Z/E. The impetus for this study was our desire to evaluate the possibility of using metal-binding precipitons that would precipitate only upon metal-to-precipiton binding and would be inert to visible light in the absence of metals. [ABSTRACT FROM AUTHOR]

In this study, we compared the adsorption of the gram-positive bacterium Bacillus subtilis with adsorption of the gram-negative bacterium Pseudomonas mendocina onto Fe-oxyhydroxide-coated and uncoated quartz grains as a function of pH and bacteria : mineral mass ratio. We studied metabolically-inactive cells in order to focus on the initial bacterial attachment mechanisms. The data show that the presence of Fe-oxyhydroxide-coatings on quartz surfaces significantly enhances the adsorption of bacteria and that in general the extent of adsorption decreases with increasing pH and with decreasing bacteria : mineral mass ratio. B. subtilis adsorbs to a greater extent than does P. mendocina onto the surface of the Fe-coated quartz. The adsorption behavior appears to be controlled by the overall surface charge of both bacterial and mineral surfaces. We model the adsorption data using a semi-empirical chemical equilibrium model that accounts for the site speciation of the adsorbing surfaces. Models describing bacterial adsorption to Fe-oxyhydroxide-coated quartz can account for changes in pH and bacteria : mineral mass ratio using one set of equilibrium constants. [ABSTRACT FROM AUTHOR]

This study explored how physical and psychosocial factors influenced the practice of health-promoting behaviors among elderly Chinese patients with type-2 diabetes. Individual structured interviews were conducted with 191 elderly Chinese attending an outpatient clinic in Hong Kong. Results showed that demographic and illness characteristics were unrelated to health practices. Participants were more likely to engage in health-promoting behaviors when they were physically well, valued their health, were confident of practicing the behaviors and viewed their illness as controllable by both doctors and themselves. The above factors exerted their respective main effects, instead of interaction effects, in predicting health practices. © 2004 SAGE Publications Ltd. [ABSTRACT FROM AUTHOR]

Objectives: To describe the epidemiology and causes of acute flaccid paralysis (AFP) in Australian children, and the clinical features of the two most common causes of AFP, Guillain-Barré syndrome and transverse myelitis.Methods: Monthly active surveillance for AFP was carried out through the Australian Paediatric Surveillance Unit, with AFP defined as 'acute onset of flaccid paralysis in one or more limbs or of bulbar paralysis in any child less than 15 years of age'.Results: Between March 1995 and December 1999, 143 cases of AFP were reported (approximately 0.8 per 100000 children < 15 years of age per annum). The age range was 2 months-14 years and 59% were boys. Out of these children, 137 (96%) were hospitalized and 47 required intensive care. No case of wild or vaccine-associated poliomyelitis was identified. The most common causes of AFP were Guillain-Barré syndrome in 67 (47%) and transverse myelitis in 27 (19%). Other diagnoses included acute disseminated encephalomyelitis, trauma, tick-bite paralysis and infantile botulism.Conclusion: The participation of paediatricians in AFP surveillance contributed to the accreditation of Australia (along with the other 36 countries of the western Pacific region) as 'polio free' by the World Health Organization in October 2000. The surveillance also provided data on the frequency of AFP and identified Guillain-Barré syndrome and transverse myelitis as the most common diagnoses. In this large national series, many other conditions that may present as non-polio AFP were identified. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify siderophore production by the aerobic bacterium, Pseudomonas mendocina, under Fe-limited conditions as a function of Fe source: supplied in dissolved form (as 30 μM Fe-EDTA), as natural Fe-containing kaolinite, and a no-Fe-added control. Siderophores are Fe(III)-specific organic ligands produced by microorganisms under conditions of Fe stress. Siderophore production was compared with previous experiments wherein Fe was supplied as hematite [Geomicrobiol. J. 17 (2000) 1]. Microbial growth increased in the order: no-added-Fe controlkaolinite>hematite≥Fe-EDTA. Thus, the bacterium was less Fe stressed in the presence of kaolinite than in the no-added-Fe control, confirming that kaolinite serves as a source of Fe to the bacterium. Although more siderophore per cell was produced in the most stressed system (no-Fe-added), more total siderophore was produced in the least stressed system (Fe-EDTA). This is due to the presence of a larger total population size in the least stressed system. Hence, the ability of a microbial population to produce siderophores as a means to access mineral-bound Fe is a complex function of both Fe stress and population size. [Copyright &y& Elsevier]

In this study, the effects of alkali and silane coupling agents and coir fiber (CF) loading on the fundamental properties of the CF-filled polypropylene (PP) composites were investigated. Mechanical properties of the PP/CF composites, such as tensile strength, tensile modulus, impact strength, and water absorption were increased by the increase of the CF loading. The inclusion of 3-aminopropyl trimethoxy silane (ATS) and tetramethoxy orthosilicate (TOS) after the alkali pretreatment for the CF increased all the mechanical properties and water desorption of the resulting composites. This trend was more evident with the increase in CF loading. The best results were obtained for PP/TOS composites as compared to other composites. SEM images of fractured samples show improved adhesion between CF and PP matrix after treatment with ATS and TOS. The horizontal rate of combustion is significantly reduced with the inclusion of Mg(OH)2 in PP/ATS and PP/TOS composites. DSC results show improved crystallization temperature, melting temperature, and melting enthalpy as compared with virgin PP. The addition of ATS and TOS after the alkali pretreatment improved the thermal stability of the resultant composites. TOS-modified CF composites showed better resistance than ATS-modified CF composites in water medium. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the extent of doping drug use among adolescents in Uppsala, Sweden, and to analyse the main reasons for the use. An anonymous multiple-choice questionnaire was distributed among pupils in the first and the third grades at high school; 2,742 pupils participated in the study. The results showed that 2.7% of the male and 0.4% of the female adolescents had used doping drugs at some time in their life. However, knowledge of how to get doping drugs far exceeded use. The main reasons for using doping drugs were to improve appearance and to enhance performance in sports. Some boys self-reported side effects of AAS. Despite the still predominantly negative attitude toward doping prevention programs have to be taken. [ABSTRACT FROM AUTHOR]

Replacing the methano (NCH2N) bridgehead with an ethano (NCH2CH2N) bridgehead affects the conformational equilibrium of the Wilcox molecular torsion balance. With a NCH2CH2N bridgehead, the phenyl and the cyclohexyl esters prefer the out conformation, whereas with the NCH2N bridgehead, they were found to prefer the folded conformation. [ABSTRACT FROM AUTHOR]

• A comprehensive investigation of concrete corrosion below the water line in gravity sewer pipes. • Neutron tomography is a powerful non-destructive technique to detect corrosion. • Calcium levels can be correlated to hardness and pH in corroded areas. • Iron uptake in cores from FeCl 2 dosed locations in below flow and tidal areas is noticable. • Softening of the concrete surface exposed to the sewerage occurs in all samples. Unexplainable concrete softening below the water line has been observed by Sydney Water in their gravity sewer network, some of which is subjected to corrosion control methods using chemical ferrous chloride (FeCl 2) dosing of the wastewater. We applied a combination of physical and chemical tools to determine the properties of the top 20 mm of concrete cores recovered from sewer pipes. These techniques consist of neutron tomographic imaging, scanning electron microscopy, hardness mapping, and pH profiling. Concrete cores were collected from roof (crown), tidal (wall) and below flow regions of gravity sewer pipes of Sydney Water's wastewater system from locations that received no treatment as well as locations dosed with FeCl 2. All samples showed a degree of softening of the surface exposed to the sewerage with an associated depletion in calcium concentration and reduced pH in the same regions. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Open cell foams are widely used in engineering which includes an application in areas, where vibration excitations can act on the structures. Therefore dynamical properties as eigenfrequencies and natural modes are of great interest. Here a modelling approach of the dynamic behaviour of open cell foams by macroscopic stochastic models will be discussed. Based on a 3D computed tomography scan of the foam, statistic and spectral analysis has been carried out to determine the parameters of the stochastic model. Additionally a vibration measurement has been done to provide eigenfrequencies, frequency transfer functions and natural modes of the real foam, which can be compared with the simulation results of the macroscopic model. [ABSTRACT FROM AUTHOR]

Background: Globally, substance use is a leading contributor to the burden of disease among young people, with far reaching social, economic and health effects. Following a finding of harmful alcohol use among 5-8-year-old children in Mbale District, Uganda, this study aims to investigate community members' views on early childhood substance use among children below the age of 10 years. Methods: In 2016, we conducted eight focus group discussions with 48 parents and 26 key informant interviews with teachers, health workers, alcohol distributors, traditional healers, religious leaders, community leaders and youth workers. We used thematic content analysis. Four participants and two research assistants reviewed and confirmed the findings. Results: Alcohol in everyday life: 'Even children on laps taste alcohol': Almost all participants confirmed the existence of and concern for substance use before age 10. They described a context where substance use was widespread in the community, especially intake of local alcoholic brews. Children would access substances in the home or buy it themselves. Those living in poor neighbourhoods or slums and children of brewers were described as particularly exposed. Using substances to cope: 'We don't want them to drink': Participants explained that some used substances to cope with a lack of food and resources for childcare, as well as traumatic experiences. This made children in deprived families and street-connected children especially vulnerable to substance use. Participants believed this was a result of seeing no alternative solution. Conclusions: To our knowledge, this is the first study to describe the context and conditions of childhood substance use before age 10 in Mbale District, Uganda. The study shows that community members attributed early childhood substance use to a social context of widespread use in the community, which was exacerbated by conditions of material and emotional deprivation. These social determinants for this practice deserve public health attention and intervention. [ABSTRACT FROM AUTHOR]

Background: Globally, substance use is a leading contributor to the burden of disease among young people, with far reaching social, economic and health effects. Following a finding of harmful alcohol use among 5-8-year-old children in Mbale District, Uganda, this study aims to investigate community members' views on early childhood substance use among children below the age of 10 years.Methods: In 2016, we conducted eight focus group discussions with 48 parents and 26 key informant interviews with teachers, health workers, alcohol distributors, traditional healers, religious leaders, community leaders and youth workers. We used thematic content analysis. Four participants and two research assistants reviewed and confirmed the findings.Results: Alcohol in everyday life: 'Even children on laps taste alcohol': Almost all participants confirmed the existence of and concern for substance use before age 10. They described a context where substance use was widespread in the community, especially intake of local alcoholic brews. Children would access substances in the home or buy it themselves. Those living in poor neighbourhoods or slums and children of brewers were described as particularly exposed. Using substances to cope: 'We don't want them to drink': Participants explained that some used substances to cope with a lack of food and resources for childcare, as well as traumatic experiences. This made children in deprived families and street-connected children especially vulnerable to substance use. Participants believed this was a result of seeing no alternative solution.Conclusions: To our knowledge, this is the first study to describe the context and conditions of childhood substance use before age 10 in Mbale District, Uganda. The study shows that community members attributed early childhood substance use to a social context of widespread use in the community, which was exacerbated by conditions of material and emotional deprivation. These social determinants for this practice deserve public health attention and intervention. [ABSTRACT FROM AUTHOR]

In this study, the electrical and piezoresistive properties of cement-based composites with binary conductive fillers consisting of carbon nanofibers (CNFs) and recycled milled carbon fibers (rMCFs) were experimentally investigated. The self-sensing capability of these composites under quasi-static and cyclic compression loads was studied. Experimental results showed that the optimal self-sensing formulation contained CNFs 1 wt% and 0.5 wt% rMCFs. Strain and temperature fiber Bragg grating sensors were embedded inside specimens to verify the load test methodology. The novelty of this work lies not only in the sustainable use of recycled carbon fibers and partial replacement of CNFs in the formulation but also in lowering the cost of production of smart cementitious products for the structural health monitoring purposes by at least $1.99/g. [ABSTRACT FROM AUTHOR]

Abstract: Die Dynamik offenporiger Schaumstrukturen wird diskutiert. Messungen realer Schaumstrukturen werden mit Computertomographen (CT) durchgeführt und anschließend über Korrelations‐ und Spektralanalyse statistisch ausgewertet. Für weißes Rauschen als Anregung des Modellschaums werden die Zeitlösungen und Autoleistungsdichtespektren berechnet und simuliert. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Shell structures are extensively used in engineering for constructions with light weight and high strength. Classical applications are covers in automotive industry, aero‐ and astronautics. For this purpose the dynamical behaviour is of interest for safety and comfort. The focus will be placed on rotating circumferential cylindrical shells. Starting with the geometrical nonlinear kinematics for the strains, the HAMILTON's principle is evaluated. In the following‐up to the calculus of variation RITZ approach is used, to compute eigenfrequencies. Afterwards the results are discussed for certain examples and compared to FE‐solutions. [ABSTRACT FROM AUTHOR]

Open cell foams are widely used in engineering which includes an application in areas, where vibration excitations can act on the structures. Therefore dynamical properties as eigenfrequencies and natural modes are of great interest. We will discuss the description of the dynamic behavior of open cell foams by stochastic macroscopic models. These are based on a computed tomography scan of the foam, which gives access to parameters and the power spectral density needed for the generation of the stochastic process. The simulation results shall be used to get an estimate of the natural frequencies. [ABSTRACT FROM AUTHOR]

In der Photovoltaik- und Halbleiterindustrie ist das Fertigen von Siliziumwafern ein aufwändiger Produktionsschritt. Die Wafer entstehen durch Zerschneiden eines mono- oder multikristallinen Siliziumblocks (Ingot). Dabei kommt das Drahttrennläppverfahren zur Anwendung. Mit dem Ziel den Drahtsägeprozess zu verbessern, wird eine Schwingungserregereinheit entwickelt. Das Gerät, betrieben mit piezoelektrischen Aktoren, ermöglicht mehrachsige Schwingungen des Siliziumblocks. Es werden für die Aktoren und die mechanische Konstruktion einzelne Modelle aufgestellt. Durch Messung des Übertragungsverhaltens gelingt anhand des gekoppelten Gesamtmodells die Identifikation von Parametern. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]